Slip composition for forming green tape suitable for continuous sintering and methods involving same

Abstract

Disclosed herein are embodiments of a slip composition. The slip composition includes particles of lithium lanthanum zirconium oxide (LLZO), a binder, a plasticizer, and a solvent. A ratio of the binder to the plasticizer is in a range from about 83:17 to about 87:13. The binder is configured to depolymerize and produce substantially no char when heated to a temperature in a range from 300°C to 600°C.

Description

SLIP COMPOSITION FOR FORMING GREEN TAPE SUITABLE FOR CONTINUOUS SINTERING AND METHODS INVOLVING SAME BACKGROUND

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. ProvisionalApplication No. 63 / 613,119 filed December 21, 2023, the content of which is incorporated herein by reference in its entirety.

[0002] The disclosure relates to sintered ceramics, and more particularly to a slip compositionfor producing a green tape for continuous sintering of lithium garnet.

[0003] Lithium-ion battery cells typically include a cathode, an anode, and a permeableseparation membrane disposed therebetween. A liquid electrolyte fills the volume in the cell, soaking the electrodes and separation membrane. Lithium ions, which are intercalated in the electrodes, move between the electrodes through the electrolyte during charging and discharging. Such lithium-ion battery cells may experience short circuits because of lithium dendrite formation through the permeable separation membrane, and the liquid electrolyte is generally volatile, which can lead to flammability issues. In contrast to such lithium-ion battery cells, solid-state batteries are considered more reliable and safer. In addition, solid-state batteries have higher energy density because of their smaller construction. Accordingly, it is desirable to replace lithium-ion battery cells with solid-state batteries, but this requires significant production of solid electrolyte materials, such as lithium garnet. SUMMARY

[0004] The following summary is a brief description of certain aspects of the presentdisclosure. The summary should not be considered as limiting of the breadth, scope, or applicability of the present disclosure.

[0005] According to aspect (1), a slip composition is provided. The slip composition includesparticles of lithium lanthanum zirconium oxide (LLZO), a binder, a plasticizer, and a solvent. A ratio of the binder to the plasticizer is in a range from about 83:17 to about 87:13. The binder is configured to depolymerize and produce substantially no char when heated to a temperature in a range from 300°C to 600°C.

[0006] According to aspect (2), the slip composition of aspect (1) is provided, furthercomprising particles of lithium carbonate.

[0007] According to aspect (3), the slip composition of aspect (2) is provided, wherein theparticles of lithium carbonate in an amount in a range from 0.5 wt% to 5 wt% of the slip composition.

[0008] According to aspect (4), the slip composition of aspect (2) or aspect (3) is provided,wherein the particles of LLZO comprise a first particle size distribution having a first median particle size d50 and the particles of lithium carbonate comprise a second particle size distribution having a second median particle size d50 and wherein the second median particle size d50 is within 30% of the first median particle size d50.

[0009] According to aspect (5), the slip composition of aspect (4) is provided, wherein the firstmedian particle size d50 is in a range from 0.4 μm to 1 μm.

[0010] According to aspect (6), the slip composition of any of aspects (2) to (5) is provided,wherein a ratio of a weight percent of the particles of LLZO to a weight percent of the particles of lithium carbonate is about 18:1 to about 32:1.

[0011] According to aspect (7), the slip composition of any of aspects (1) to (6) is provided,comprising the particles of LLZO in an amount in a range from about 50 wt% to about 53 wt% of the slip composition.

[0012] According to aspect (8), the slip composition of any of aspects (1) to (7) is provided,wherein the particles of LLZO are passivated particles of LLZO.

[0013] According to aspect (9), the slip composition of any of aspects (1) to (8) is provided,further comprising a dispersant.

[0014] According to aspect (10), the slip composition of aspect (9) is provided, wherein thedispersant is a polyester / polyamine condensation polymer.

[0015] According to aspect (11), the slip composition of aspect (9) or aspect (10) is provided,comprising the dispersant in an amount in a range from about 0.5 wt% to about 1.5 wt% of the slip composition.

[0016] According to aspect (12), the slip composition of any of aspects (1) to (11) is provided,wherein the plasticizer comprises at least one of a phthalate, dibutyl maleate, propylene carbonate polyol, or triethylene glycol bis (2-ethylhexanoate).

[0017] According to aspect (13), the slip composition of any of aspects (1) to (12) is provided,comprising the plasticizer in an amount in a range from about 0.5 wt% to about 2 wt% of the slip composition.

[0018] According to aspect (14), the slip composition of any of aspects (1) to (13) is provided,wherein the solvent comprises at least one of methyl ethyl ketone, toluene, dimethyl carbonate, dioxane, dioxolane, anisole, or tetrahydrofuran.

[0019] According to aspect (15), the slip composition of any of aspects (1) to (14) is provided,comprising the solvent in an amount in a range from about 30 wt% to about 45 wt% of the slip composition.

[0020] According to aspect (16), the slip composition of any of aspects (1) to (15) is provided,comprising the binder in an amount in a range from about 5.5 wt% to about 8.5 wt% of the slip composition.

[0021] According to aspect (17), the slip composition of any of aspects (1) to (16) is provided,wherein the binder comprises polypropylene carbonate or a derivative thereof.

[0022] According to aspect (18), the slip composition of any of aspects (1) to (16) is provided,wherein the binder comprises at least one of polybutylene carbonate, poly(alkylene carbonate), poly(ethylene carbonate), poly(propylene / cyclohexene carbonate), poly(cyclohexene carbonate), or derivatives thereof.

[0023] According to aspect (19), the slip composition of any of aspects (1) to (18) is provided,comprising a viscosity of 3 Pa∙s or less at a shear rate of 10 s-1or higher.

[0024] According to aspect (20), the slip composition of any of aspects (1) to (19) is provided,wherein the LLZO comprises at least one of (i) Li7-3aLa3Zr2LaO12with L = Al, Ga, or Fe and 0 < a < 0.33; (ii) Li7La3-bZr2MbO12with M = Bi, Ca, or Y and 0 < b < 1; (iii) Li7-cLa3(Zr2-cNc)O12with N = In, Si, Ge, Sn, V, W, Te, Nb, or Ta and 0 < c < 1; (iv) Li7-xLa3(Zr2-x, Mx)O12 with M = In, Si, Ge, Sn, Sb, Sc, Ti, Hf, V, W, Te, Nb, Ta, Al, Ga, Fe, Bi, Y, Mg, Ca, or combinations thereof and 0 < x < 1; or a combination thereof.

[0025] According to aspect (21), a green tape is provided. The green tape includes an inorganiccomponent including particles of LLZO and an organic component comprising a binder and a plasticizer. The binder is configured to depolymerize and produce substantially no char when heated to a temperature in a range from 300°C to 600°C. The green tape includes the organic component in an amount in a range from 10 wt% to 20 wt%.

[0026] According to aspect (22), the green tape of aspect (21) is provided, wherein theinorganic component further comprises particles of lithium carbonate.

[0027] According to aspect (23), the green tape of aspect (22) is provided, wherein the particlesof LLZO comprise a first particle size distribution having a first median particle size d50 and the particles of lithium carbonate comprise a second particle size distribution having a second median particle size d50 and wherein the second median particle size d50 is within 10% of the first median particle size d50.

[0028] According to aspect (24), the green tape of aspect (23) is provided, wherein the firstmedian particle size d50 is in a range from 0.4 μm to 1 μm.

[0029] According to aspect (25), the green tape of any of aspects (22) to (24) is provided,wherein a ratio of a weight percent of the particles of LLZO to a weight percent of the particles of lithium carbonate is about 18:1 to about 32:1.

[0030] According to aspect (26), the green tape of any of aspects (21) to (25) is provided,wherein the organic component further comprises a dispersant.

[0031] According to aspect (27), the green tape of aspect (26) is provided, wherein thedispersant comprises a polyester / polyamine condensation polymer.

[0032]

[0033] According to aspect (28), the green tape of any of aspects (21) to (27) is provided,wherein the plasticizer comprises at least one of a phthalate, dibutyl maleate, propylene carbonate polyol, or triethylene glycol bis (2-ethylhexanoate).

[0034] According to aspect (29), the green tape of any of aspects (21) to (28) is provided,wherein the binder comprises polypropylene carbonate or a derivative thereof.

[0035] According to aspect (30), the green tape of any one of aspects (21) to (28) is provided,wherein the binder comprises at least one of polybutylene carbonate, poly(alkylene carbonate), poly(ethylene carbonate), poly(propylene / cyclohexene carbonate), poly(cyclohexene carbonate), or derivatives thereof.

[0036] According to aspect (31), the green tape of any of aspects (21) to (30) is provided,wherein the LLZO comprises at least one of (i) Li7-3aLa3Zr2LaO12 with L = Al, Ga, or Fe and 0 < a < 0.33; (ii) Li7La3-bZr2MbO12with M = Bi, Ca, or Y and 0 < b < 1; (iii) Li7-cLa3(Zr2-cNc)O12with N = In, Si, Ge, Sn, V, W, Te, Nb, or Ta and 0 < c < 1; (iv) Li7-xLa3(Zr2-x, Mx)O12 with M= In, Si, Ge, Sn, Sb, Sc, Ti, Hf, V, W, Te, Nb, Ta, Al, Ga, Fe, Bi, Y, Mg, Ca, or combinations thereof and 0 < x < 1; or a combination thereof.

[0037] According to aspect (32), the green tape of any of aspects (21) to (31) is provided,wherein the green tape exhibits an endothermic signature at a temperature in a range from 190 °C to 210 °C as measured using differential scanning calorimetry.

[0038] According to aspect (33), the green tape of any of aspects (21) to (32) is provided,comprising a tensile strength of at least 0.5 MPa.

[0039] According to aspect (34), the green tape of aspect (33) is provided, comprising anelongation at break of at least 10%.

[0040] According to aspect (35), the green tape of any of aspects (21) to (34) is provided,comprising a storage modulus of at least 1 GPa as measured at room temperature.

[0041] According to aspect (36), the green tape of any of aspects (21) to (35) is provided,wherein the green tape is disposed on a carrier film.

[0042] According to aspect (37), the green tape of aspect (36) is provided, wherein the carrierfilm comprises silicone-coated polyethylene terephthalate.

[0043] According to aspect (38), the green tape of aspect (36) or aspect (37) is provided,wherein a peel force to separate the green tape from the carrier film is less than 0.1 N on average.

[0044] According to aspect (39), the green tape of any of aspects (21) to (38) is provided,comprising a thickness of 40 μm to 60 μm.

[0045] According to aspect (40), the green tape of any of aspects (21) to (39) is provided,comprising a length of at least 150 feet.

[0046] According to aspect (41), a method of preparing a green tape is provided. In themethod, a slip composition according to the first aspect is tape cast onto a carrier film, and the solvent is evaporated to produce the green tape.

[0047] According to aspect (42), the method of aspect (41) is provided, further comprisingpreparing the slip composition, wherein preparing the slip composition comprises: ball milling the solvent and a dispersant to form a first mixture; adding particles of lithium carbonate powder to the first mixture to form a second mixture; balling milling the second mixture; adding the particles of LLZO to the second mixture to form a third mixture; ball milling thethird mixture; adding the binder and the plasticizer to form a fourth mixture; and balling milling the fourth mixture.

[0048] According to aspect (43), the method of aspect (42) is provided, wherein the secondmixture is ball milled for a time in a range of 36 hours to 72 hours at 20 rpm to 100 rpm before adding the particles of LLZO.

[0049] According to aspect (44), the method of aspect (42) or aspect (43) is provided, whereinthe third mixture is ball milled for a time in a range from 36 hours to 72 hours at 20 rpm to 100 rpm before adding the binder and the plasticizer.

[0050] According to aspect (45), the method of any of aspects (41) to (44) is provided, whereinduring evaporating a drying front of the green tape is symmetric across a width of the green tape.

[0051] According to aspect (46), the method of any of aspects (41) to (45) is provided, whereinthe carrier film comprises silicone-coated polyethylene terephthalate.

[0052] According to aspect (47), the method of any of aspects (41) to (46) is provided, whereinthe solvent is evaporated at a temperature in a range from 45 °C to 90 °C.

[0053] According to aspect (48), the method of any of aspects (41) to (47) is provided, whereinthe green tape comprises a thickness of 40 μm to 60 μm.

[0054] Additional features and advantages will be set forth in the detailed description whichfollows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0055] It is to be understood that both the foregoing general description and the followingdetailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. BRIEFDESCRIPTION OF THEDRAWINGS

[0056] The accompanying drawings are included to provide a further understanding, and areincorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and operation of the various embodiments. In the drawings:

[0057] FIG. 1 is a schematic representation of a solid-state battery cell including a solidelectrolyte formed form a lithium garnet strip, according to one or more exemplary embodiments;

[0058] FIG. 2 is a flow diagram of a method for preparing a lithium garnet slip composition,according to one or more exemplary embodiments;

[0059] FIG.3 is a graph of viscosity as a function of shear rate for a slip composition accordingto one or more exemplary embodiments;

[0060] FIG. 4 is a flow diagram of a method for forming a green tape of lithium garnet from aslip composition according to one or more exemplary embodiments;

[0061] FIG. 5 is a schematic representation of a drying chamber that can be used for tapecasting a slip composition according to one or more exemplary embodiments;

[0062] FIG. 6 is a graph of tensile stress vs. tensile strain for green tapes of two differentthicknesses according to one or more exemplary embodiments;

[0063] FIG. 7 is a graph of peel force for a green tape of two different thicknesses accordingto one or more exemplary embodiments;

[0064] FIG.8 is a graph of the ratio (tan δ) of the storage modulus to loss modulus as a functionof temperature for calculating a composite glass transition temperature of a green tape, according to one or more exemplary embodiments;

[0065] FIG. 9 is a graph comparing the storage moduli for green tapes of two differentcompositions, according to one or more exemplary embodiments;

[0066] FIG. 10 is a graph depicting mass loss and heat flow during binder burnout of a greentape as measured via thermogravimetric analysis – differential scanning calorimetry, according to one or more exemplary embodiments;

[0067] FIG. 11 are x-ray diffraction (XRD) spectra for lithium garnet particles, bisque-firedgreen tape, and dense-fired green tape, according to one or more exemplary embodiments; and

[0068] FIG. 12 is a photograph of a green tape having solvent evaporated therefrom to definea drying front that is substantially symmetrical about a longitudinal axis of the green tape, according to one or more exemplary embodiments.DETAILED DESCRIPTION

[0069] Reference will now be made in detail to various embodiments of a lithium garnet slipcomposition, green tape cast therefrom, and sintered lithium garnet ceramic tape formed from the green tape, examples of which are illustrated in the accompanying drawings. As will be discussed more fully below, the production of lithium garnet in a continuous manner is difficult at least in part because of the need to sinter lithium garnet in a dry and / or inert atmosphere. In such an environment, the organic component of the slip composition leaves residual char, preventing good bonding between particles during sintering. Further, Applicant has found that the slip composition must be carefully prepared to avoid inhomogeneity during tape casting, which can lead to warping or breaking of the green tape. The slip composition disclosed herein can be tape cast to produce a mechanically robust green tape that has negligible residual char after sintering. These and other aspects and advantages of the disclosed slip composition, green tape, and continuous lithium garnet ceramic ribbon will be described more fully below. The embodiments discussed herein are presented by way of illustration and not limitation.

[0070] Solid state batteries are considered a promising technology for secondary batteries withhigh capacity and high energy density for such applications as electric vehicles, consumer electronics, and energy storage, amongst other possibilities. Solid state batteries are expected to provide higher performance and higher safety at lower cost compared to conventional wet electrolyte lithium-ion batteries. FIG.1 schematically depicts a solid-state battery (SSB) cell 10 according to one or more exemplary embodiments. The SSB cell 10 includes a cathode 12, an anode 14, and a solid electrolyte 16. The solid electrolyte 16 is disposed between the cathode 12 and the anode 14. In one or more embodiments, the cathode 12 is comprised of a lithium- based oxide (such as lithium nickel cobalt aluminum oxide or lithium cobalt oxide), lithium- based phosphates (such as lithium iron phosphate), or vanadium oxide, for example. In one or more embodiments, the anode 14 is comprised of carbon, a titanate, a lithium alloy, or lithium metal. In one or more embodiments, the solid electrolyte 16 is comprised of a lithium garnet, such as lithium lanthanum zirconium oxide (LLZO) garnet having the formula of, e.g., Li7La3Zr2O12. LLZO garnet is considered a promising electrolyte for solid-state batteries because it has a high Li-ion conductivity (10-4to 10-5Scm-1), a high Young’s modulus (150 GPa), and a wide electrochemical window (> 5 V vs. Li+ / Li), and compatibility with lithium metal.

[0071] In one or more embodiments, the SSB cell 10 also includes a cathode current collector18 and an anode current collector 20. In one or more embodiments, the current collectors 18, 20 are comprised of aluminum, copper, nickel, titanium, or stainless steel, among other possibilities. In one or more embodiments, the current collectors 18, 20 are foil, meshed foils, foams, or carbon coated foils, amongst other possibilities.

[0072] The cathode 12, anode 14, solid electrolyte 16, and current collectors 18, 20 of the SSBcell 10 may be contained in a housing 22 (such as a pouch) having a positive lead 24 and a negative lead 26 in electrical communication with the cathode 12 and anode 14, respectively. In the embodiment shown in FIG. 1, the SSB cell 10 includes a single cathode 12, a single anode 14, and a single solid electrolyte 16, but in one or more other embodiments, the SSB cell 10 includes a single or a plurality of cathodes 16, a single or a plurality of anodes 14, and a single or a plurality of solid electrolytes 16, in particular in a stacked arrangement with alternating electrode (cathode 12 or anode 14) and solid electrolyte 16. A plurality of SSB cells 10 may be connected to form a battery, and multiple batteries may be connected to form a module, which can, in turn, be assembled into a battery pack. The battery pack can then be used as a power source for, e.g., an electric vehicle.

[0073] Lithium garnet for solid electrolytes is typically produced by sintering particles oflithium garnet. In order to economically and efficiently produce such sintered lithium garnet, it is desirable to use a continuous, roll-to-roll process. However, production of lithium garnet in this manner is not currently feasible because lithium garnet is reactive in air, making sintering dense, flat, and electrochemically / mechanically suitable tapes difficult using existing sintering methods. In particular, the reactive nature of lithium garnet requires sintering in a dry and / or inert environment. However, in such an environment, the organic components of the tape are not completely burnt off, which leaves residual carbon between particles that prevents strong bonding between the particles. Further, preparation of suitable slip compositions has proven to be difficult, and existing slip compositions tend to be in homogenous, leading to warpage of the sintered ceramic tape.

[0074] According to the present disclosure, Applicant has developed a slip system, green body,and forming unit operation that is able to produce a continuous ribbon of lithium garnet in a roll-to-roll process. In particular, Applicant has determined that, in order to produce a green body suitable for continuous sintering, the slip system should not produce a residual carbon upon sintering and should allow for heterogeneous dispersion of the ceramic powders in the tape. As will be described more fully below, these objectives are achieved by preparing a slipcomposition that (1) utilizes a binder that produces low residual carbon when pyrolyzed, (2) matches the particle size distribution of the ceramic components in the slip, (3) carefully disperses the ceramic components in the slip.

[0075] In one or more embodiments, the slip composition comprises lithium garnet particles,binder, plasticizer, and solvent. In one or more embodiments, the slip composition may further comprise lithium carbonate particles, which may be used to compensate for lithium volatility during sintering. Further, in one or more embodiments, the slip composition may further comprise dispersant.

[0076] In one or more embodiments, the lithium garnet particles may be an LLZO composition.Optionally, dopant elements may substitute at least one of Li, La, or Zr in LLZO. For example,the lithium garnet can comprise at least one of: (i) Li7-3aLa3Zr2LaO12, with L=Al, Ga or Fe and 0<a<0.33; (ii) Li7La3-bZr2MbO12, with M=Bi, Ca, or Y and 0<b<1; (iii) Li7-cLa3(Zr2-cNc)O12, with N=In, Si, Ge, Sn, V, W, Te, Nb, or Ta and 0<c<1; (iv) Li7-xLa3(Zr2-x, Mx)O12, with M=In, Si, Ge, Sn, Sb, Sc, Ti, Hf, V, W, Te, Nb, Ta, Al, Ga, Fe, Bi, Y, Mg, Ca, or combinations thereof and 0<x<1, or a combination thereof. For example, the LLZO may be doped with Ta and have the formula of Li6.5La3Zr1.5Ta0.5O12. The lithium garnet compositions described herein are merely exemplary, and other lithium garnet compositions may also be used.

[0077] In one or more embodiments, the lithium garnet particles have a median particle size(d50) in a range from 0.4 μm to 1 μm, such as in a range from 0.5 μm to 1 μm, in a range from 0.6 μm to 1 μm, in a range from 0.7 μm to 1 μm, in a range from 0.8 μm to 1 μm, in a range from 0.9 μm to 1 μm, in a range from 0.4 μm to 0.9 μm, in a range from 0.5 μm to 9 μm, in a range from 0.6 μm to 0.9 μm, in a range from 0.7 μm to 0.9 μm, in a range from 0.8 μm to 0.9 μm, in a range from 0.4 μm to 0.8 μm, in a range from 0.5 μm to 0.8 μm, in a range from 0.6 μm to 0.8 μm, in a range from 0.7 μm to 0.8 μm, in a range from 0.4 μm to 0.7 μm, in a range from 0.5 μm to 0.7 μm, in a range from 0.6 μm to 0.7 μm, in a range from 0.4 μm to 0.6 μm, in a range from 0.5 μm to 0.6 μm, in a range from 0.4 μm to 0.5 μm, in a range from 0.3 μm to 1.5 μm, in a range from 0.25 μm to 2 μm, in a range from 0.25 μm to 3 μm, or in a range from 0.1 μm to 5 μm.

[0078] In one or more embodiments, the lithium garnet particles may be passivated with shellsof lithium carbonate and lithium / proton exchanged garnet as described in U.S. Publication No. 2022 / 0384841 (“PASSIVATED LLZO PARTICLES AND TAPE CASTING OF LLZO FILMS,” filed May 28, 2021, and published on December 1, 2022), the entire contents of which are incorporated herein by reference thereto. Such passivated particles are able to be stored inambient air without concern for further reaction of the lithium garnet with water and carbon dioxide in the air. Also, advantageously, the passivated lithium garnet particles do not react with other components of the slip composition, such as the binder. In particular, Applicant has found that pristine lithium garnet, in certain circumstances, may react with one or more of the components of the slip composition, such as the binder (especially polypropylene carbonate).

[0079] In one or more embodiments, the slip composition comprises the lithium garnetparticles in an amount in a range from about 50 wt% to about 53 wt% of the slip composition, in a range from about 50.5 wt% to about 53 wt%, in a range from about 51 wt% to about 53 wt%, in a range from about 51.5 wt% to about 53 wt%, in a range from about 52 wt% to about 53 wt%, in a range from about 52.5 wt% to about 53 wt%, in a range from about 50 wt% to about 52.5 wt%, in a range from about 50.5 wt% to about 52.5 wt%, in a range from about 51 wt% to about 52.5 wt%, in a range from about 52 wt% to about 52.5 wt%, in a range from about 50 wt% to about 52 wt%, in a range from about 50.5 wt% to about 52 wt%, in a range from about 51 wt% to about 52 wt%, in a range from about 51.5 wt% to about 52 wt%, in a range from about 50 wt% to about 51.5 wt%, in a range from about 50.5 wt% to about 51.5 wt%, in a range from about 51 wt% to about 51.5 wt%, in a range from about 50 wt% to about 51 wt%, in a range from about 50.5 wt% to about 51 wt%, in a range from about 50 wt% to about 50.5 wt%, in a range from about 49 wt% to about 53 wt%, in a range from about 49 wt% to about 54 wt%, or in a range from about 48 wt% to about 55 wt%. In one or more particular embodiments, the slip composition comprises the lithium garnet particles in an amount in a range of about 51 wt%.

[0080] In one or more embodiments, the binder comprises a polymer producing a low residualcarbon when pyrolyzed during sintering. In one or more embodiments, the binder comprises a carbonate, such as at least one of polypropylene carbonate, polybutylene carbonate, poly(alkylene carbonate), poly(ethylene carbonate), poly(propylene / cyclohexene carbonate), poly(cyclohexene carbonate), or derivatives thereof. Such binders tend to degrade via depolymerization instead of decomposing into residual carbon or char.

[0081] In one or more embodiments, the slip composition comprises binder in an amount in arange from about 6 wt% to about 8 wt% of the slip composition, such as in a range from about 6.5 wt% to about 8 wt%, in a range from about 7 wt% to about 8 wt%, in a range from about 7.5 wt% to about 8 wt%, in a range from about 6 wt% to about 7.5 wt%, in a range from about 6.5 wt% to about 7.5 wt%, in a range from about 7 wt% to about 7.5 wt%, in a range from about 6 wt% to about 7 wt%, in a range from about 6.5 wt% to about 7 wt%, in a range fromabout 6 wt% to about 6.5 wt%, in a range from about 5.5 wt% to about 8.5 wt%, in a range from about 5 wt% to about 9 wt%, or in a range from about 4.5 wt% to about 9.5 wt%. In one or more particular embodiments, the slip composition comprises binder in an amount of about 7 wt% of the slip composition.

[0082] In one or more embodiments, the plasticizer is a phthalate (such as dibutyl phthalate,diisobutyl phthalate, or butyl benzyl phthalate), dibutyl maleate, propylene carbonate polyol, or triethylene glycol bis (2-ethylhexanoate). In one or more embodiments, the slip composition comprises the plasticizer in an amount in a range from about 0.5 wt% to about 2 wt%, such as in a range from about 0.75 wt% to about 2 wt%, in a range from about 1 wt% to about 2 wt%, in a range from about 1.25 wt% to about 2 wt%, in a range from about 1.5 wt% to about 2 wt%, in a range from about 1.75 wt% to about 2 wt%, in a range from about 0.5 wt% to about 1.75 wt%, in a range from about 0.75 wt% to about 1.75 wt%, in a range from about 1 wt% to about 1.75 wt%, in a range from about 1.25 wt% to about 1.75 wt%, in a range from about 1.5 wt% to about 1.75 wt%, in a range from about 0.5 wt% to about 1.5 wt%, in a range from about 0.75 wt% to about 1.5 wt%, in a range from about 1 wt% to about 1.5 wt%, in a range from about 1.25 wt% to about 1.5 wt%, in a range from about 0.5 wt% to about 1.25 wt%, in a range from about 0.75 wt% to about 1.25 wt%, in a range from about 1 wt% to about 1.25 wt%, in a range from about 0.5 wt% to about 1 wt%, in a range from about 0.75 wt% to about 1 wt%, in a range from about 0.5 wt% to about 0.75 wt%, in a range from about 0.5 wt% to about 2.5 wt%, in a range from about 0.75 wt% to about 2.5 wt%, in a range from about 1 wt% to about 3 wt%, in a range from about 0.5 wt% to about 4 wt%. In one or more particular embodiments, the slip composition comprises the plasticizer in an amount of about 1 wt% of the slip composition.

[0083] In one or more embodiments, the slip composition comprises binder and plasticizer ina ratio of about 83:17 to about 87:13, in particular about 85:15.

[0084] In one or more embodiments, the solvent can be any of a variety of suitable solvents,such as methyl ethyl ketone (MEK), toluene, dimethyl carbonate, dioxane, dioxolane, anisole, or tetrahydrofuran.

[0085] In one or more embodiments, the slip composition comprises solvent in an amount in arange from about 30 wt% to about 40 wt% of the slip composition, such as in a range from about 31 wt% to about 40 wt%, in a range from about 32 wt% to about 40 wt%, in a range from about 33 wt% to about 40 wt%, in a range from about 34 wt% to about 40 wt%, in a range from about 35 wt% to about 40 wt%, in a range from about 36 wt% to about 40 wt%, in a range from about 37 wt% to about 40 wt%, in a range from about 38 wt% to about 40 wt%, in a range fromabout 39 wt% to about 40 wt%, in a range from about 30 wt% to about 39 wt%, in a range from about 31 wt% to about 39 wt%, in a range from about 32 wt% to about 39 wt%, in a range from about 33 wt% to about 39 wt%, in a range from about 34 wt% to about 39 wt%, in a range from about 35 wt% to about 39 wt%, in a range from about 36 wt% to about 39 wt%, in a range from about 37 wt% to about 39 wt%, in a range from about 38 wt% to about 39 wt%, in a range from about 30 wt% to about 38 wt%, in a range from about 31 wt% to about 38 wt%, in a range from about 32 wt% to about 38 wt%, in a range from about 33 wt% to about 38 wt%, in a range from about 34 wt% to about 38 wt%, in a range from about 35 wt% to about 38 wt%, in a range from about 36 wt% to about 38 wt%, in a range from about 37 wt% to about 38 wt%, in a range from about 30 wt% to about 37 wt%, in a range from about 31 wt% to about 37 wt%, in a range from about 32 wt% to about 37 wt%, in a range from about 33 wt% to about 37 wt%, in a range from about 34 wt% to about 37 wt%, in a range from about 35 wt% to about 37 wt%, in a range from about 36 wt% to about 37 wt%, in a range from about 30 wt% to about 36 wt%, in a range from about 31 wt% to about 36 wt%, in a range from about 32 wt% to about 36 wt%, in a range from about 33 wt% to about 36 wt%, in a range from about 34 wt% to about 36 wt%, in a range from about 35 wt% to about 36 wt%, in a range from about 30 wt% to about 35 wt%, in a range from about 31 wt% to about 35 wt%, in a range from about 32 wt% to about 35 wt%, in a range from about 33 wt% to about 35 wt%, in a range from about 34 wt% to about 35 wt%, in a range from about 30 wt% to about 34 wt%, in a range from about 31 wt% to about 34 wt%, in a range from about 32 wt% to about 34 wt%, in a range from about 33 wt% to about 34 wt%, in a range from about 30 wt% to about 33 wt%, in a range from about 31 wt% to about 33 wt%, in a range from about 32 wt% to about 33 wt%, in a range from about 30 wt% to about 32 wt%, in a range from about 31 wt% to about 32 wt%, in a range from about 30 wt% to about 31 wt%, in range from about 30 wt% to about 45 wt%, in a range from about 35 wt% to about 50 wt%, or in a range from about 30 wt% to about 55 wt%. In one or more particular embodiments, the slip composition comprises solvent in an amount in a range from about 35 wt% to about 38 wt% of the slip composition, in particular about 37 wt%.

[0086] As mentioned above, the slip composition may also include particles of lithiumcarbonate to compensate for lithium volatility during sintering. In one or more embodiments, the slip composition comprises particles of lithium carbonate in an amount in a range from about 0.5 wt% to about 5 wt%, such as in an amount in a range from about 1 wt% to about 5 wt%, in an amount in a range from about 1.5 wt% to about 5 wt%, in an amount in a range from about 2 wt% to about 5 wt%, in an amount in a range from about 2.5 wt% to about 5 wt%,in an amount in a range from about 3 wt% to about 5 wt%, in an amount in a range from about 3.5 wt% to about 5 wt%, in an amount in a range from about 4 wt% to about 5 wt%, in an amount in a range from about 4.5 wt% to about 5 wt%, in an amount in a range from about 1 wt% to about 4 wt%, in an amount in a range from about 1.5 wt% to about 4 wt%, in an amount in a range from about 2 wt% to about 4 wt%, in an amount in a range from about 2.5 wt% to about 4 wt%, in an amount in a range from about 3 wt% to about 4 wt%, in an amount in a range from about 3.5 wt% to about 4 wt%, in an amount in a range from about 1 wt% to about 3 wt%, in an amount in a range from about 1.5 wt% to about 3 wt%, in an amount in a range from about 2 wt% to about 3 wt%, in an amount in a range from about 2.5 wt% to about 3 wt%, in an amount in a range from about 1 wt% to about 2 wt%, or in an amount in a range from about 1.5 wt% to about 2 wt%.

[0087] In one or more embodiments, a ratio of the weight percent of lithium garnet particles inthe slip composition to the weight percent of lithium carbonate particles in the slip composition is in a range from about 18:1 to about 32:1, in particular about 19:1.

[0088] In one or more embodiments, the particles of lithium carbonate have a median particlesize (d50) in a range from 0.4 μm to 1 μm, such as in a range from 0.5 μm to 1 μm, in a range from 0.6 μm to 1 μm, in a range from 0.7 μm to 1 μm, in a range from 0.8 μm to 1 μm, in a range from 0.9 μm to 1 μm, in a range from 0.4 μm to 0.9 μm, in a range from 0.5 μm to 9 μm, in a range from 0.6 μm to 0.9 μm, in a range from 0.7 μm to 0.9 μm, in a range from 0.8 μm to 0.9 μm, in a range from 0.4 μm to 0.8 μm, in a range from 0.5 μm to 0.8 μm, in a range from 0.6 μm to 0.8 μm, in a range from 0.7 μm to 0.8 μm, in a range from 0.4 μm to 0.7 μm, in a range from 0.5 μm to 0.7 μm, in a range from 0.6 μm to 0.7 μm, in a range from 0.4 μm to 0.6 μm, in a range from 0.5 μm to 0.6 μm, or in a range from 0.4 μm to 0.5 μm, in a range from 0.3 μm to 1.5 μm, in a range from 0.25 μm to 2 μm, in a range from 0.25 μm to 3 μm, or in a range from 0.1 μm to 5 μm.

[0089] In particular, in one or more embodiments, the median particle size of the particles oflithium carbonate are selected to match the median particle size of the particles of lithium garnet, in particular such that the median particle sizes are within 30%, in particular within 20%, more particularly within 10%, and most particular within 5%. Advantageously, matching the particles sizes of the lithium garnet and lithium carbonate provides improves homogeneous dispersion of the particles as well as improving sintering kinetics.

[0090] Further, as mentioned above, the slip composition may also include a dispersant. Toproduce a green tape configured for continuous sintering, Applicant has found that apolyester / polyamine condensation polymer is particularly suitable. An example of a commercially available dispersant suitable for use in the slip composition is Hypermer KD-1 (Croda International plc, Snaith, UK). In one or more embodiments, the slip composition comprises dispersant in an amount in a range from about 0.5 wt% to about 1.5 wt% of the slip composition, such as in a range from about 0.75 wt% to about 1.5 wt%, in a range from about 1 wt% to about 1.5 wt%, in a range from about 1.25 wt% to about 1.5 wt%, in a range from about 0.5 wt% to about 1.25 wt%, in a range from about 0.75 wt% to about 1.25 wt%, in a range from about 1 wt% to about 1.25 wt%, in a range from about 0.5 wt% to about 1 wt%, in a range from about 0.75 wt% to about 1 wt%, in a range from about 0.5 wt% to about 0.75 wt%, in a range from about 0.5 wt% to about 2 wt%, or in a range from about 0.25 wt% to about 3 wt%. In one or more particular embodiments, the slip composition comprises dispersant in an amount of about 0.8 wt% of the slip composition.

[0091] FIG. 2 provides a flow diagram describing a method 100 of preparing the slipcomposition according to the present disclosure. As will be discussed, the method of preparing the slip composition involves a two-stage dispersion of the inorganic components (particles of lithium carbonate and of lithium garnet) in the organic components (binder, plasticizer, dispersant, and solvent). In a first step 101 of the method 100, the dispersant and solvent are mixed, in particular using ball milling. In one or more embodiments, the ball milling utilizes yttria-stabilized zirconia (YSZ) media. In one or more such embodiments, the YSZ media includes media having a diameter of 12 mm and media having a diameter of 6.5 mm, in particular in a ratio of about 650:300 by weight. In one or more embodiments, ball milling in the first step 101 takes place for a time in a range of 0.5 hours to 4 hours, in particular about 2 hours, at a mixing speed in a range of 20 rpm to 100 rpm, in particular about 50 rpm.

[0092] In a second step 102 of the method 100, the particles of lithium carbonate are added tothe dispersant / solvent mixture and mixed, in particular by ball milling. In one or more such embodiments, the ball milling in the second step 102 takes place for a time in a range of 36 hours to 72 hours, in particular about 48 hours, at a mixing speed in a range of 20 rpm to 100 rpm, in particular about 50 rpm.

[0093] In a third step 103 of the method 100, the particles of lithium garnet are added to themixture of the lithium carbonate particles, dispersant, and solvent and mixed, in particular by ball milling. In one or more such embodiments, the ball milling in the third step 103 takes place for a time in a range of 36 hours to 72 hours, in particular about 48 hours, at a mixing speed in a range of 20 rpm to 100 rpm, in particular about 50 rpm.

[0094] In a fourth step 104 of the method 100, the binder and plasticizer are added to themixture of the particles of lithium garnet, particles of lithium carbonate, dispersant, and solvent, in particular by ball milling. In one or more such embodiments, the ball milling in the fourth step 104 takes place for a time in a range of 12 hours to 48 hours, in particular about 24 hours, at a mixing speed in a range of 20 rpm to 100 rpm, in particular about 50 rpm.

[0095] A slip composition of the composition described above and prepared according to theforegoing method has a slip viscosity of about 3 Pa∙s or less. FIG. 3 provides a graph of the viscosity (Pa∙s) as a function of shear rate (s-1). For a slip composition prepared according to the present disclosure represented in FIG.3, the slip viscosity was less than 0.8 Pa∙s for a shear rate of about 10 s-1and greater. The shear rate during tape casting can be controlled, at least in part, by the tape casting speed and the height of the tape casting blade.

[0096] FIG. 4 provides another flow diagram of a method 200 for preparing a green tape fromthe slip composition. In a first step 201 of the method 200, the slip composition is tape cast onto a carrier film. In one or more embodiments, the carrier film comprises a backer layer and a release layer. In one or more such embodiments, the carrier film comprises silicone-coated polyethylene terephthalate (PET). Further, in one or more such embodiments, the slip is tape cast to contact the release layer (e.g., silicone-coated) side of the carrier film.

[0097] In a second step 202 of the method 200, the tape cast slip composition is dried to removethe solvent and form a green tape.

[0098] FIG. 5 schematically illustrates a solvent-annealing apparatus 301 configured toperform the first two steps 201, 202 of the method 200 of preparing the green tape. As shown,the solvent-annealing apparatus 301 comprises a casting chamber 309 including a castingapparatus 311. The casting apparatus 311 is configured to form a solvent-containing ceramic green tape 328 from the slip composition as described above. In aspects, as shown, the solvent-annealing apparatus 301 can optionally include an adapter 313 configured to transition thesolvent-containing ceramic green tape from the casting apparatus 311 onto the carrier film 316. In aspects, as shown, the casting chamber 309 can be in fluid communication with a solvent reservoir 305 configured to contain the solvent 307. In further aspects, the solvent 307 can correspond to one of the one or more solvents in the slip composition mixture used to form the solvent-containing ceramic green tape. The solvent 307 in the solvent reservoir 305 can maintain a casting vapor pressure of the solvent in an environment of the casting chamber 309.

[0099] As shown in FIG. 5, the solvent-annealing apparatus 301 comprises a solvent-ladenchamber 321. In aspects, as shown, the solvent-laden chamber 321 can be separated from thecasting chamber 309 by a baffle 306. An orifice 319 is provided therebetween and isconfigured to allow the solvent-containing ceramic green tape 328 to pass therethrough indirection 317. In aspects, as shown, the solvent-annealing apparatus 301 can optionally include at least one additional source 315 of solvent 307, which is shown in another solvent reservoir.The at least one additional source 315 of solvent 307, if present, comprises the same materialas the solvent 307. The at least one additional source 315 of solvent 307 can be configured tomaintain a chamber vapor pressure of the solvent. Alternatively, the chamber vapor pressure can be maintained by the flow of solvent vapor from the casting chamber 309 to the solvent- laden chamber 321 (e.g., through the orifice 319). In aspects, the chamber vapor pressure ofthe solvent in the solvent-laden chamber 321 is configured to be less than a casting vaporpressure of the solvent in the casting chamber 309. In aspects, as shown, the solvent-annealingapparatus 301 can comprise one or more heating apparatuses 323, 325, 326 configured to heatand / or maintain a chamber temperature of the solvent-laden chamber 321. In further aspects, the chamber temperature of the solvent-laden chamber 321 can be greater than a casting temperature of the casting chamber 309. In further aspects, a temperature encountered by asolvent-containing ceramic green tape 328 carried on the carrier film 316 in the direction 317can increase. For example, a first heating apparatus 323 can be configured to maintain a first temperature lower than a second temperature that the second heating apparatus 325 is configured to be maintained, which is lower than a third temperature that the third heating apparatus 326 is configured to maintain. Although three heating apparatuses 323, 325, 326 are shown in the embodiment depicted, it is to be understood that one, two, or more than three heating apparatuses can be provided in other aspects.

[0100] As shown in FIG.5, the solvent-annealing apparatus 301 comprises a drying chamber331. In aspects, as shown, the solvent-laden chamber 321 can be separated from the dryingchamber 331 by a baffle 324. As shown, the solvent-laden chamber 321 is positioned betweenthe casting chamber 309 and the drying chamber 331. Also, an orifice 329 is provided throughthe baffle 324 and is configured to allow the solvent-containing ceramic green tape 328 to passtherethrough in direction 327. In aspects, a drying vapor pressure of the solvent in the drying chamber 331 is configured to be less than the chamber vapor pressure of the solvent in the solvent-laden chamber 321. The drying chamber 331 comprises a distal end 303 opposite thebaffle 324, and the drying chamber 331 comprises a proximate end 304 proximate the baffle324 and opposite the distal end 303. The solvent-containing ceramic green tape 328 isconfigured to be transported by the carrier film 316 in the direction 327 from the proximateend 304 of the drying chamber 331 to the distal end 303 of the drying chamber 331. Substantially all of the solvent in the solvent-containing ceramic green tape 328 can be removed to become a solvent-free ceramic green tape by the time that it travels through the outlet 339 of the solvent-annealing apparatus 301 in direction 337.

[0101] As shown in FIG. 5, the solvent-annealing apparatus 301 comprises a ventilationsystem 340. The ventilation system 340 can be configured to circulate an atmosphere from a substantially solvent-free environment through the drying chamber 331, for example, to remove solvent from the solvent-containing ceramic green tape 328. As shown, the ventilation system 340 can comprise a plurality of orifices (e.g., inlet 341, air filter 345, and / or outlet 347). In aspects, as shown the ventilation system 340 includes an inlet 341 at a distal end 303 of the drying chamber 331 configured to introduce the atmosphere 342 from the substantially solvent- free environment into the drying chamber 331. In further aspects, a temperature of theatmosphere introduced by the inlet 341 can comprise a predetermined temperature that can beachieved, for example, using a heating apparatus 343. The predetermined temperature can correspond to a drying temperature of the drying chamber 331 that can be greater than a chamber temperature of the solvent-laden chamber 321. As shown, the ventilation system 340includes an outlet 347 at the proximate end 304 of the drying chamber 331 that is configuredto remove the atmosphere 348 at the proximate end 304. Providing the inlet at the distal end and the outlet at the proximate end enables the atmosphere to flow in a direction opposite the direction 327 that the solvent-containing ceramic green tape 328 is transported, which can enable the atmosphere to remove solvent continuously from the solvent-containing ceramic green tape as the atmosphere flows by the solvent-containing ceramic green tape and / or through the drying chamber. Additionally, providing the outlet at the proximate end of the drying chamber can enable the any solvent from the environment of the solvent-laden chamber that passes through the orifice 329 to be removed. In aspects, as shown, the plurality of orifices can further comprise an additional orifice (e.g., air filter 345) positioned between the proximateend 304 and the distal end 303 (e.g., between the outlet 347 and the inlet 341). In furtheraspects, as shown, the additional orifice (e.g., air filter 345) can be configured to introduce additional atmosphere 346 (e.g., substantially solvent-free environment) into the drying chamber 331. For example, atmosphere 346 is introduced to the drying chamber 331 through the air filter 345, which can reduce particulate matter in the atmosphere that could otherwise impair a surface quality of the resulting solvent-free ceramic green tape and / or sintered article. Although not shown, it is to be understood that the substantially solvent-free atmosphereintroduced through the inlet 341 can also be filtered (e.g., HEPA) and / or comprise a low level of particulates (e.g., satisfying one or more clean room standards for atmosphere). Introducing atmosphere at both the distal end and at another location (between the distal end and the proximate end) can facilitate removal of solvent from the solvent-containing ceramic green- body at a predetermined rate.

[0102] Aspects of methods of solvent annealing will now be discussed with reference to thesolvent-annealing apparatus 301 schematically illustrated in FIG.5 and the green tape 328. As mentioned above, a first step 201 of the method 200 involves casting the slip composition asdescribed above to form a solvent-containing ceramic green tape 328 in the casting chamber309. In aspects, the casting chamber 309 can comprise a casting vapor pressure of a solvent corresponding to a solvent in the solvent-containing ceramic green-body 328. In further aspects, the casting vapor pressure can be about 100 Pascals or more, about 500 Pascals or more, about 1,000 Pascals or more, about 5,000 Pascals or more, about 10,000 Pascals or more, about 20,000 Pascals or more, about 30,000 Pascals or more, about 40,000 Pascals or more, about 50,000 Pascals or more, about 60,000 Pascals or more, or within 10,000 Pascals of a vapor pressure of the solvent at its boiling point. In further aspects, the casting vapor pressure can be in a range from about 100 Pascals to about 50,000 Pascals, from about 500 Pascals to about 50,000 Pascals, from about 1,000 Pascals to about 50,000 Pascals, from about 5,000 Pascals to about 40,000 Pascals, from about 10,000 Pascals to about 30,000 Pascals, from about 20,000 Pascals to about 30,000 Pascals, or any range or subrange therebetween. As discussed above, the casting vapor pressure can be maintained and / or provided by solvent 307 from a solvent reservoir 305 in fluid communication with the casting chamber 309. The solvent reservoir 305 can be maintained at a reservoir temperature that is greater than a casting temperature of the casting chamber 309, which can facilitate volatilization of the solvent 307 from the solvent reservoir 305. For example, the reservoir temperature can be about 50°C or more, about 60°C or more, about 65°C or more, about 70°C or more, about 75°C or more, about 80°C or more, about 95°C or less, about 90°C or less, about 85°C or less, or about 80°C or less. In aspects, the reservoir temperature can be in a range from about 50°C to about 95°C, from about 55°C to about 90°C, from about 60°C to about 85°C, from about 65°C to about 80°C, from about 70°C to about 80°C, or any range or subrange therebetween. In aspects, the casting vapor pressure can correspond to a vapor pressure of one or more of the solvent of the slip composition, such as MEK, toluene, dimethyl carbonate, dioxane, dioxolane, anisole, tetrahydrofuran, or combinations thereof. In further aspects, the casting vapor pressure cancorrespond to a vapor pressure of a single solvent, and that solvent can be the same as a solvent in the composition of the solvent-containing ceramic green tape 328. Providing the casting vapor pressure (e.g., about 100 Pascals or more, from about 1,000 Pascals to about 50,000 Pascals) can limit an amount of solvent evaporating from the solvent-containing ceramic green- body during casting and / or in the casting chamber, which can be associated with a good surface quality of the resulting solvent-free ceramic green tape and / or sintered ceramic ribbon.

[0103] After casting the solvent-containing ceramic green tape 328 (e.g., in the castingchamber 309) in a first step 201 of the method 200, as shown in FIG.5, the solvent-containing ceramic green tape 328 may then be dried in the second step 202 of the method. Drying may involve first solvent-annealing and then removal of the solvent from the green tape. In such amethod, the green tape 328 can be transported to the solvent-laden chamber 321 for solventannealing, for example, by being transported by the carrier film 316 through the orifice 319 in direction 317. In aspects, a chamber vapor pressure of the solvent in the solvent-laden chamber 321 can be less than the casting vapor pressure of the solvent in the casting chamber 309. In further aspects, the chamber vapor pressure can be maintained through one or more of atmosphere comprising the casting vapor pressure entering the solvent-laden chamber 321(e.g., through orifice 319), volatilization of solvent from the optional, additional source 315 ofsolvent 307, the controlled rate of solvent leaving the solvent-containing ceramic green tape328, and combinations thereof. In further aspects, the additional source 315 of solvent 307may not be maintained at a separate temperature (unlike solvent reservoir 305), and / or theadditional source 315 of solvent 307 can comprise one or more containers (e.g., dishes) for thecondensation and re-evaporation of the solvent 307 in the solvent-laden chamber 321.

[0104] In further aspects, the chamber vapor pressure can be about 20 Pascals or more, about50 Pascals or more, about 100 Pascals or more, about 500 Pascals or more, about 1,000 Pascals or more, about 5,000 Pascals or more, about 10,000 Pascals or more, about 20,000 Pascals or more, about 50,000 Pascals or less, about 40,000 Pascals or less, about 30,000 Pascals or less, about 20,000 Pascals or less, about 10,000 Pascals or less, or about 8,000 Pascals or less. In further aspects, the chamber vapor pressure can be in a range from about 20 Pascals to about 50,000 Pascals, from about 50 Pascals to about 50,000 Pascals, 100 Pascals to about 50,000 Pascals, from about 500 Pascals to about 50,000 Pascals, from about 1,000 Pascals to about 50,000 Pascals, from about 5,000 Pascals to about 40,000 Pascals, from about 10,000 Pascals to about 30,000 Pascals, from about 20,000 Pascals to about 30,000 Pascals, or any range or subrange therebetween. Providing the chamber vapor pressure (e.g., about 20 Pascals or more,from about 1,000 Pascals to about 50,000 Pascals, and / or less than the casting vapor pressure) can facilitate the controlled removal of solvent from the solvent-containing ceramic green tape.

[0105] In aspects, a chamber temperature of the solvent-laden chamber 321 can be greaterthan a casting temperature of the casting chamber 309. In further aspects, the chamber temperature of the solvent-laden chamber 321 can be about 20°C or more, about 40°C or more, about 50°C or more, about 60°C or more, about 65°C or more, about 70°C or more, for example, in a range from about 20°C to about 120°C, from about 40°C to about 100°C, from about 50°C to about 90°C, from about 60°C to about 80°C, or any range or subrangetherebetween. As shown in FIG. 5, one or more heating apparatuses 323, 325, 326 can heatthe solvent-laden chamber 321 and / or the solvent-containing ceramic green tape 328 beingtransported therethrough. In further aspects, the one or more heating apparatuses 323, 325, 326 can generate multiple heating zones and / or a temperature gradient in the solvent-laden chamber 321 such that the temperature encountered by the solvent-containing ceramic green tape 328 increases as it is transported through solvent-laden chamber 321 (e.g., in the direction 317). In one or more embodiments, the heating apparatus 323 defines a heating zone having a temperature in a range from 20°C to 60°C, the heating apparatus 325 defines a heating zone having a temperature in a range from 50°C to 90°C, and the heating apparatus 326 defines a heating zone having a temperature in a range from 80°C to 120°C. Providing an increasing temperature encountered by the solvent-containing ceramic green tape being transported through the solvent-laden ceramic green tape can facilitate the controlled and continuous removal of solvent from solvent-laden ceramic green tape as part of the solvent-annealing process. In this regard, the temperature in each heating zone defined by the heating apparatuses 323, 325, 326 may be indexed to boiling point of the solvent used in the green tape 328. For example, for MEK solvent having a boiling point of about 80°C, the first heating zone of the heating apparatus 323 may be selected to be below the boiling point, such as about 45°C, the second heating zone of the heating apparatus 325 may be selected to be approximately at the boiling point of 80°C , and the third heating zone of the heating apparatus 326 may be selected to be above the boiling point, such as about 90°C.

[0106] In aspects, a time that a section of the solvent-containing ceramic green tape 328spends in the solvent-laden chamber 321 (e.g., time being heated in the solvent-laden chamber) can be about 3 minutes or more, about 4 minutes or more, about 5 minutes or more, about 6 minutes or more, about 8 minutes or more, about 10 minutes or more, about 30 minutes or less, about 20 minutes or less, about 10 minutes or less, about 9 minutes or less, about 8 minutes orless, about 7 minutes or less, about 6 minutes or less, or about 5 minutes or less. In aspects, the time that the solvent-containing ceramic green tape 328 spends in the solvent-laden chamber 321 (e.g., time being heated in the solvent-laden chamber) can be in a range from about 3 minutes to about 30 minutes, from about 3 minutes to about 20 minutes, from about 3 minutes to about 10 minutes, from about 4 minutes to about 9 minutes, from about 5 minutes to about 8 minutes, from about 6 minutes to about 7 minutes, or any range or subrange therebetween. In aspects, the ceramic green tape 328 is tape cast and travels through the solvent-annealing apparatus 301 at a speed in a range from 5 inches / minute to 10 inches / minute, such as in a range from 6 inches / minute to 10 inches / minute, in a range from 7 inches / minute to 10 inches / minute, in a range from 8 inches / minute to 10 inches / minute, in a range from 9 inches / minute to 10 inches / minute, in a range from 5 inches / minute to 9 inches / minute, in a range from 6 inches / minute to 9 inches / minute, in a range from 7 inches / minute to 9 inches / minute, in a range from 8 inches / minute to 9 inches / minute, in a range from 5 inches / minute to 8 inches / minute, in a range from 6 inches / minute to 8 inches / minute, in a range from 7 inches / minute to 8 inches / minute, in a range from 5 inches / minute to 7 inches / minute, in a range from 6 inches / minute to 7 inches / minute, or in a range from 5 inches / minute to 6 inches / minute.

[0107] In aspects, after transporting the solvent-containing ceramic green-body 328 throughthe solvent-laden chamber 321, as shown in FIG. 5, methods can comprise transporting the solvent-containing ceramic green tape 328 to the drying chamber 331, for example, on the carrier film 316 through the orifice 329 in the direction 327. In further aspects, a drying vapor pressure of the solvent in the drying chamber 331 can be less than the chamber vapor pressure and the casting vapor pressure. In further aspects, the drying vapor pressure can be about 20 Pascals or less, about 15 Pascals or less, about 10 Pascals or less, about 5 Pascals or less, or about 1 Pascal or less. Providing a drying vapor pressure less of about 20 Pascals or less can facilitate the removal of solvent from the solvent-containing ceramic green tape to form the solvent-free ceramic green tape. In further aspects, the drying chamber 331 can be maintained at a drying temperature that is greater than the casting temperature and the chamber temperature. In further aspects, the drying temperature can be within about 20°C, within 15°C, or within about 10°C of a boiling point of the solvent. In further aspects, the chamber temperature can be about 70°C or more, about 75°C or more, about 80°C or more, about 85°C or more, about 90°C or more, about 130°C or less, about 110°C or less, about 100°C or less, or about 90°C or less. In further aspects, the chamber temperature can be in a range from about70°C to about 130°C, from about 75°C to about 110°C, from about 80°C to about 100°C, from about 85°C to about 90°C, or any range or subrange therebetween. In further aspects, as shown in FIG.5, the drying temperature can be maintained by heating the atmosphere and / or solvent- containing ceramic green tape in the drying chamber with a heating apparatus 343. In even further aspects, the heating can occur by heating an atmosphere introduced to the drying chamber 331 from a substantially solvent-free environment by flowing the atmosphere around the heating apparatus 343, for example, positioned in the inlet 341 although the heating apparatus can be positioned in other locations in other aspects.

[0108] In aspects, as shown in FIG. 5, drying the solvent-containing ceramic green tape cancomprise introducing an atmosphere from a substantially solvent-free environment into the drying chamber 331. In further aspects, as shown, the atmosphere 342 can be introduced through the inlet 341, which can be positioned at the distal end 303 of the drying chamber. Additionally, as shown, atmosphere 348 can be removed from the drying chamber through anoutlet 347 positioned at the proximate end 304 of the drying chamber 331. Providing the inletat the distal end and the outlet at the proximate end enables the atmosphere to flow in a direction opposite the direction 327 that the solvent-containing ceramic green tape 328 is transported, which can enable the atmosphere to remove solvent continuously from the solvent-containing ceramic green tape as the atmosphere flows by the solvent-containing ceramic green tape and / or through the drying chamber. Additionally, providing the outlet at the proximate end of the drying chamber can enable any solvent from the environment of the solvent-laden chamber that passes through the orifice 329 to be removed. In further aspects, atmosphere 342, 346 can be introduced from the substantially solvent-free environment at a plurality of locations, including the inlet 341 at the distal end 303 and at an additional location (e.g., air filter 345) ata location between the distal end 303 and the proximate end 304 and / or between the inlet 341and the outlet 347. Introducing atmosphere at both the distal end and at another location (between the distal end and the proximate end) can facilitate removal of solvent from the solvent-containing ceramic green tape at a predetermined rate. In further aspects, an average speed of atmosphere over the solvent-containing ceramic green tape in the drying chamber 331 (e.g., as measured at location 351) can be about 0.1 meters per second (m / s), about 0.08 m / s, about 0.05 m / s, about 0.03 m / s, about 0.02 m / s, about 0.01 m / s, or about 0.01 m / s or more, for example, in a range from about 0.01 m / s to about 0.1 m / s, from about 0.01 m / s to about 0.08 m / s, from about 0.01 m / s to about 0.05 m / s, from about 0.01 m / s to about 0.03 m / s, from about 0.01 m / s to about 0.02 m / s, or any range or subrange therebetween. Providing a low averagespeed of atmosphere (e.g., about 0.1 m / s or less, or from about 0.01 m / s to about 0.1 m / s) over the solvent-containing ceramic green tape can facilitate uniform drying and / or good surface quality of the resulting solvent-free ceramic green tape and / or resulting sintered ceramic ribbon. The average speed of atmosphere over the solvent-containing ceramic green-body can be less than an average speed of atmosphere at other locations in the drying chamber (e.g., location 353 near the additional source of atmosphere between the distal end 303 and the proximate end 304, or location 355 near the outlet 347 at the proximate end 304), which can facilitate high surface quality of the resulting article while exchanging larger amounts of atmosphere through the drying chamber 331 to keep the chamber vapor pressure low.

[0109] After the green tape 328 passes through the solvent-annealing apparatus 301, thesolvent will be substantially if not entirely removed. At this point, the green tape 328 will comprise an inorganic component comprising the particles of lithium garnet and the particles of lithium carbonate and an organic component comprising binder, plasticizer, and dispersant. In one or more embodiments, the green tape 328 comprises the organic component in an amount in a range of 10 wt% to 20 wt% of the green tape 328, in particular about 15 wt%.

[0110] Returning to the method 200 of FIG. 4, the method 200 may further include a thirdstep 203 of taking the green tape and carrier film up on a spool for storage or transport. For example, the green tape may be transported to another processing line for sintering.

[0111] A green tape as described is mechanically robust enough for roll-to-roll, continuousprocessing. In particular, the green tape possesses sufficient tensile strength to not fall apart during continuous processing. In one or more embodiments, the green tape has a tensile strength of at least 0.5 MPa, in particular at least 0.6 MPa.

[0112] Further, when disposed on the carrier film, the green tape can be separated from thecarrier film at an average peel force of 0.1 N or less, in particular 0.07 N or less, and most particularly 0.05 N or less. If the peel force is too high because of a strong interaction between the green tape and the carrier film, the green tape could break when removing the carrier film.

[0113] In one or more embodiments, the green tape comprises a composite glass transitiontemperature (Tg) based on the polymer and ceramic components of present in the green tape. The composite glass transition temperature (Tg) can be determined based on the ratio (Tan δ) of the storage modulus of the green tape to the loss modulus of the green tape as a function of temperature. A peak in the ratio (Tan δ) at a specific temperature corresponds to the composite glass transition temperature (Tg). The composite glass transition temperature should be low enough to produce a flexible film while also exhibiting a storage modulus high enough topermit handling of the green tape. In one or more embodiments, the composite glass transition temperature of the green tape is 25 °C (standard room temperature) or higher. In this way, the green tape possesses some flexibility while also being rigid enough for handling at room temperature (Tg). In one or more embodiments, the glass transition temperature (Tg) of the green tape is about 26 °C, and in one or more embodiments, the glass transition temperature (Tg) is 30 °C or less. The glass transition temperature (Tg) referenced herein is determined from the ratio (Tan δ) of storage modulus to loss modulus as measured using dynamic mechanical analysis. Further, in one or more embodiments, the green tape comprises a storage modulus of at least 0.5 GPa at 25 °C, in particular at least 0.7 GPa at 25 °C, and most particularly at least 1 GPa at 25 °C. The storage modulus as referenced herein is measured using dynamic mechanical analysis.

[0114] In one or more embodiments, the green tape produced according to the presentdisclosure is suitable for continuous sintering. In one or more embodiments, the green tape is paid off from a spool, such as the spool that takes up the green tape after tape casting and drying. In one or more embodiments, the green tape undergoes an initial step of burning out the organic component of the green tape. During burnout, the organic material is removed from the green tape. In one or more embodiments, the green tape is heated to a temperature in a range from 300 °C to 600 °C for a time of 0.5 minutes to 15 minutes. Further, during burnout, the binder depolymerizes without producing residual char. Thereafter, in one or more embodiments, the green tape is advanced through a furnace in which the green tape is heated to a temperature in a range from 1000°C to 1300°C for a time of 10 minutes to 60 minutes to sinter the green tape into a continuous ribbon ceramic. In one or more embodiments, the sintering process comprises two stages. In one or more such embodiments, the first stage is a bisque firing performed at a temperature in a range from 1000 °C to 1200 °C for a time of 10 minutes to 60 minutes. Further, in one or more such embodiments, the second stage is a dense- firing performed at a temperature in a range from 1100°C to 1300°C for a time of 10 minutes to 60 minutes. After exiting the furnace, the continuous ribbon ceramic is able to be wound on a spool. The sintering is performed in inert or dry air environment, such as in an argon environment.

[0115] In one or more embodiments, the continuous ribbon ceramic of lithium garnet has athickness in a range from 25 μm to 150 μm, in a range from 40 μm to 130 μm, or less than or equal to 150 μm but greater than or equal to 25 μm, greater than or equal to 30 μm, greater than or equal to 35 μm, greater than or equal to 40 μm, greater than or equal to 45 μm, greater thanor equal to 50 μm, greater than or equal to 55 μm, greater than or equal to 60 μm, greater than or equal to 65 μm, greater than or equal to 70 μm, greater than or equal to 75 μm, greater than or equal to 80 μm, greater than or equal to 85 μm, greater than or equal to 90 μm, greater than or equal to 95 μm, greater than or equal to 100 μm, greater than or equal to 105 μm, greater than or equal to 110 μm, greater than or equal to 115 μm, greater than or equal to 120 μm, greater than or equal to 125 μm, greater than or equal to 130 μm, greater than or equal to 135 μm, greater than or equal to 140 μm, or greater than or equal to 145 μm.

[0116] Alternatively or additionally, in one or more embodiments, the continuous ribbonceramic of lithium garnet has a width in a range from 1 cm to 100 cm, in a range from 1 cm to 50 cm, or less than or equal to 100 cm but greater than or equal to 5 cm, greater than or equal to 10 cm, greater than or equal to 15 cm, greater than or equal to 20 cm, greater than or equal to 25 cm, greater than or equal to 35 cm, greater than or equal to 45 cm, greater than or equal to 55 cm, greater than or equal to 65 cm, greater than or equal to 75 cm, greater than or equal to 85 cm, or greater than or equal to 95 cm.

[0117] Alternatively or additionally, in one or more embodiments, the continuous ribbonceramic of lithium garnet has a length in a range from 10 cm to 100 m, in a range from 10 cm to 1 m, or less than or equal to 100 m but greater than or equal to 1 m, greater than or equal to 2 m, greater than or equal to 3 m, greater than or equal to 5 m, greater than or equal to 10 m, greater than or equal to 15 m, greater than or equal to 20 m, greater than or equal to 30 m, greater than or equal to 50 m, or greater than or equal to 75 m.

[0118] EXPERIMENTAL EXAMPLES

[0119] EXPERIMENT 1

[0120] Slip compositions were prepared according to Table 1, below. As can be seen fromTable 1, the slip compositions each included particles of LLZO, particles of lithium carbonate (Li2CO3), polypropylene carbonate (PPC) binder (MW=- 250 kg / mol, available from Empower Materials, Inc.), dibutyl phthalate (DBP) plasticizer (99%, 524980, available from Sigma- Aldrich), Hypermer KD-1 dispersant (available from Croda Initial plc), and methyl ethyl ketone (MEK) solvent (ACS grade, available from Sigma-Aldrich).Table 1. Experimental Slip Compositions, Components in wt%

[0121] For Examples 1-3 and 5, the ratio of binder to plasticizer was 85:15, and for Example4, the ratio of binder to plasticizer was 80:20. Further, in the slip compositions, the excess lithium content provided by lithium carbonate was varied form 3 wt% to 5 wt% of the total inorganic component (LLZO + Li2CO3). Additionally, in each of the example compositions, the particle sizes of the LLZO and the lithium carbonate had matching particle size distributions. The slip compositions were prepared according to the method 100 of FIG. 2. Further, viscosity as a function of shear rate was measured for the slip composition of Example 3, and the graph is provided in FIG.3. As can be seen, the viscosity was less than 0.8 Pa∙s for shear rates of 10 s-1and above, which is below the desired maximum slip velocity of 3 Pa∙s as shear rates associated with tape casting.

[0122] EXPERIMENT 2

[0123] Each of the example compositions was tape cast onto a silicon-coated PET carrierfilm at tape thicknesses in a range from 40 μm to 60 μm. The tapes were cast having lengths in a range from 30 feet to 40 feet. Examples 1 and 2 were also tape cast at lengths of 150 feet and over 200 feet, respectively. In total, over 2000 feet of tape using the compositions of Examples 1-4 were cast over the course of the experiments described herein. The tapes were cast according to the method 200 of FIG.4 and using a tape caster and drying chamber 300 as described in relation to FIG.5.

[0124] The tapes of the slip compositions of Examples 1-4 were cast at a casting speed ofabout 6 inches / minute, and Applicant observed a symmetric drying front about 6 inches to 12 inches from the exit of the drying chamber. The drying front can be seen in the photograph of FIG.12 (with the arrows showing the direction of travel). The drying front 350 is generally shown with curved dashed line on the green tape 328. As can be seen, the drying front 350 is substantially symmetric about a longitudinal axis 360 of the green tape 328. While the dryingfront 350 shown in FIG. 12 is generally parabolic, the drying front 350 may have a different shape in other embodiments; although, in embodiments, the shape and area of the drying front 350 on each side of the longitudinal axis 360 will be substantially the same, e.g., within 20%. Further, Applicant placed a backlight beneath the tape to observe the uniformity of the distribution of the binder and ceramic particles in the tape. Applicant did not observe any streaks that would indicate inhomogeneity of the binder and particles.

[0125] EXPERIMENT 3

[0126] Mechanical properties of the tape cast from the slip composition of Example 3 weredetermined. A first tape was cast at a thickness of 45 μm, and a second tape was cast at a thickness of 53 μm. In particular, the tensile strength of the tapes was determined. FIG. 6 provides a graph of tensile stress as a function of tensile strain (ε). As can be seen in FIG.6, the tensile strength for both tapes was greater than 0.5 MPa, in particular greater than about 0.6 MPa.

[0127] Further, the peel strength of each tape was measured, which represents the forcerequired to remove the green tape from the silicone-coated PET carrier film. FIG.7 provides a graph of the peel force (10-2N) as a function of the normalized position along the length. As can be seen in FIG. 7, the average peel force for the first, thinner tape was 0.024 N, and the peel force for the second, thicker tape was 0.054 N.

[0128] Qualitatively, Applicant observed that the sample green tapes formed from the slipcomposition of Example 3 were able to be satisfactorily removed from the carrier film. However, Example 4, which included a slightly higher amount of plasticizer relative to the binder, did not release as well from the carrier film. It is believed that enhanced electrostatic interactions formed between the carrier film and the green tape of the slip composition of Example 4 prevented continuous release of the green tape from the carrier film.

[0129] EXPERIMENT 4

[0130] The composite glass transition temperature (Tg) and the storage modulus weremeasured for green tapes formed from slip compositions of Examples 3 and 4. FIG.8 provides a graph of the ratio (Tan δ) of storage modulus to loss modulus as a function of temperature. As can be seen in FIG. 8, the green tape formed from the slip composition of Example 3 exhibited a composite glass transition temperature of 26.3 °C, and the green tape formed from the slip composition of Example 4 exhibited a lower composite glass transition temperature of 19.6 °C. The composite glass transition temperature was measured using dynamic mechanical analysis as discussed above. During tape casting and sintering operations, Applicant observedimproved handleability for the green tape (Example 3) having the higher composite glass transition temperature.

[0131] FIG. 9 graphically depicts the storage modulus as measured using dynamicmechanical analysis at standard room temperature of green tapes formed from the slip compositions of Examples 3 and 4. As can be seen, the storage modulus for the green tape formed from the slip composition of Example 3 was over 1.0 GPa. However, the green tape formed from the slip composition of Example 4 exhibited a storage modulus of less than 0.5 GPa. The lower storage modulus of the green tape formed from the slip composition of Example 4 is believed to be related to the higher plasticizer content. Again, the storage modulus relates to the handleability of the green tape. A higher storage modulus is associated with a green tape that is more mechanical robust and can withstand casting, peeling, and continuous sintering operations.

[0132] EXPERIMENT 5

[0133] The green tapes formed from the slip compositions of Examples 3 and 4 weresubjected to binder burnout up to a temperature of 600 °C, and relative mass and heat flow were measured using thermogravimetric analysis – differential scanning calorimetry (TGA- DSC). FIG.10 depicts the results of the TGA-DSC with relative mass being on the top portion of the graph and heat flow being on the bottom portion of the graph. As shown in the top portion of FIG.10, the green tapes of both Examples 3 and 4 exhibited a mass change event at approximately 197 °C, which corresponds to a temperature at which the green tapes exhibit a dip in heat flow. A dip in heat flow represents an endothermic reaction. Specifically, instead of combusting to produce char in an exothermic reaction, the binder decomposes by depolymerization in an endothermic reaction, which produces negligible residual carbon or char.

[0134] The TGA-DSC analysis was performed at the beginning of each tape as well as at theend to investigate the uniformity of the tape properties along the length of the green tape. Applicant found that the mass loss curves exhibited a high degree of uniformity, in particular less than 1% difference in total mass loss between samples. Accordingly, the properties of the green tapes were substantially uniform along the length.

[0135] EXPERIMENT 6

[0136] Green tapes formed from each of Examples 1-4 were continuously sintered in afurnace using a two-stage firing process. The first stage was a bisque firing performed at a temperature of 1125°C for 60 minutes, and the second stage was a dense firing performed at atemperature of 1200 °C for 60 minutes. Examples 1-3 were able to be continuously sintered and wound on a spool. The green tape formed from the slip composition of Example 4, having the higher plasticizer content, did not perform as well as the green tapes prepared from the slip compositions of Examples 1-3.

[0137] FIG. 11 provides x-ray diffraction (XRD) spectra for lithium garnet LLZO particles,for the bisque-fired tape, and for the dense-fired tape. As can be seen in FIG. 11, the LLZO particles exhibit peaks characteristic of lithium carbonate and of lanthanum zirconium oxide. As the firing proceeds, the peaks decrease and are eliminated in the final dense-fired continuous ribbon ceramic.

[0138] EXPERIMENT 7

[0139] In order to demonstrate the suitability of the continuous ribbon ceramic of lithiumgarnet for a solid-state electrolyte, the sintered tapes were evaluated for their electrical performance. A sintered tape formed from the slip composition of Example 3 was cut into 15 mm diameter discs and etched to remove any carbonates formed on the surface after sintering and storage in air. The etchant was 1 M hydrochloric acid, and the etching time was 3 minutes. The etching reduced the thickness of the sintered tape from 36 µm to 25 µm. Pouch cells were assembled using the discs as solid electrolytes between a lithium metal anode with a 300 nm interlayer of gold and a lithium-nickel-manganese-cobalt-oxide cathode. The pouch cells were then subjected to various charging and discharging cycles, such as charging and discharging over a 12 hour period (C / 12), charging and discharging over an 8 hour period (C / 8), charging and discharging over a 6 hour period charging and discharging over a 3 hour period (C / 3), charging and discharging over a 2 hour period (C / 2), and charging and discharging over a 1 hour period (1C). For short term charging / discharging testing, the pouch cells were subjected to various different combinations of charging cycles over 13 rounds of cycling, and for long term cycling, the pouch cells were subjected to C / 3 charging and C / 8 discharging until failure. The charging cycles demonstrated the ability to incorporate a continuously cast and sintered lithium garnet ceramic into a solid-state battery construction.

[0140] Unless otherwise expressly stated, it is in no way intended that any method set forthherein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, asused herein, the article “a” is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.

[0141] It will be apparent to those skilled in the art that various modifications and variationscan be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations, and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A slip composition, comprising:particles of lithium lanthanum zirconium oxide (LLZO); a binder; a plasticizer; and a solvent; wherein a ratio of the binder to the plasticizer is in a range from about 83:17 to about 87:13; and wherein the binder is configured to depolymerize and produce substantially no char when heated to a temperature in a range from 300°C to 600°C.

2. The slip composition of claim 1, further comprising particles of lithium carbonate.

3. The slip composition of claim 2, wherein the particles of lithium carbonate in anamount in a range from 0.5 wt% to 5 wt% of the slip composition.

4. The slip composition of claim 2 or claim 3, wherein the particles of LLZO comprise afirst particle size distribution having a first median particle size d50 and the particles of lithium carbonate comprise a second particle size distribution having a second median particle size d50 and wherein the second median particle size d50 is within 30% of the first median particle size d50.

5. The slip composition of claim 4, wherein the first median particle size d50 is in arange from 0.4 μm to 1 μm.

6. The slip composition of any of claims 2-5, wherein a ratio of a weight percent of theparticles of LLZO to a weight percent of the particles of lithium carbonate is about 18:1 to about 32:1.

7. The slip composition of any of claims 1-6, comprising the particles of LLZO in anamount in a range from about 50 wt% to about 53 wt% of the slip composition.

8. The slip composition of any of claims 1-7, wherein the particles of LLZO arepassivated particles of LLZO.

9. The slip composition of any of claims 1-8, further comprising a dispersant.

10. The slip composition of claim 9, wherein the dispersant is a polyester / polyamine condensation polymer.

11. The slip composition of claim 9 or claim 10, comprising the dispersant in an amount in a range from about 0.5 wt% to about 1.5 wt% of the slip composition.

12. The slip composition of any of claims 1-11, wherein the plasticizer comprises at least one of a phthalate, dibutyl maleate, propylene carbonate polyol, or triethylene glycol bis (2- ethylhexanoate).

13. The slip composition of any of claims 1-12, comprising the plasticizer in an amount in a range from about 0.5 wt% to about 2 wt% of the slip composition.

14. The slip composition of any of claims 1-13, wherein the solvent comprises at least one of methyl ethyl ketone, toluene, dimethyl carbonate, dioxane, dioxolane, anisole, or tetrahydrofuran.

15. The slip composition of any of claims 1-14, comprising the solvent in an amount in a range from about 30 wt% to about 45 wt% of the slip composition.

16. The slip composition of any of claims 1-15, comprising the binder in an amount in a range from about 5.5 wt% to about 8.5 wt% of the slip composition.

17. The slip composition of any of claims 1-16, wherein the binder comprises polypropylene carbonate or a derivative thereof.

18. The slip composition of any of claims 1-16, wherein the binder comprises at least one of polybutylene carbonate, poly(alkylene carbonate), poly(ethylene carbonate), poly(propylene / cyclohexene carbonate), poly(cyclohexene carbonate), or derivatives thereof.

19. The slip composition of any of claims 1-18, comprising a viscosity of 3 Pa∙s or less at a shear rate of 10 s-1or higher.

20. The slip composition of any of claims 1-19, wherein the LLZO comprises at least one of (i) Li7-3aLa3Zr2LaO12with L = Al, Ga, or Fe and 0 < a < 0.33; (ii) Li7La3-bZr2MbO12with M = Bi, Ca, or Y and 0 < b < 1; (iii) Li7-cLa3(Zr2-cNc)O12with N = In, Si, Ge, Sn, V, W, Te, Nb, or Ta and 0 < c < 1; (iv) Li7-xLa3(Zr2-x, Mx)O12 with M = In, Si, Ge, Sn, Sb, Sc, Ti, Hf, V, W, Te, Nb, Ta, Al, Ga, Fe, Bi, Y, Mg, Ca, or combinations thereof and 0 < x < 1; or a combination thereof.

21. A green tape, comprising: an inorganic component comprising particles of lithium lanthanum zirconium oxide (LLZO); an organic component comprising a binder and a plasticizer; wherein the binder is configured to depolymerize and produce substantially no char when heated to a temperature in a range from 300°C to 600°C; and wherein the green tape comprises the organic component in an amount in a range from 10 wt% to 20 wt%.

22. The green tape of claim 21, wherein the inorganic component further comprises particles of lithium carbonate.

23. The green tape of claim 22, wherein the particles of LLZO comprise a first particle size distribution having a first median particle size d50 and the particles of lithium carbonate comprise a second particle size distribution having a second median particle size d50 and wherein the second median particle size d50 is within 10% of the first median particle size d50.

24. The green tape of claim 23, wherein the first median particle size d50 is in a range from 0.4 μm to 1 μm.

25. The green tape of any of claims 22-24, wherein a ratio of a weight percent of the particles of LLZO to a weight percent of the particles of lithium carbonate is about 18:1 to about 32:

1.

26. The green tape of any of claims 21-25, wherein the organic component further comprises a dispersant.

27. The green tape of claim 26, wherein the dispersant comprises a polyester / polyamine condensation polymer.

28. The green tape of any of claims 21-27, wherein the plasticizer comprises at least one of a phthalate, dibutyl maleate, propylene carbonate polyol, or triethylene glycol bis (2- ethylhexanoate).

29. The green tape of any of claims 21-28, wherein the binder comprises polypropylene carbonate or a derivative thereof.

30. The green tape of any one of claims 21-28, wherein the binder comprises at least one of polybutylene carbonate, poly(alkylene carbonate), poly(ethylene carbonate), poly(propylene / cyclohexene carbonate), poly(cyclohexene carbonate), or derivatives thereof.

31. The green tape of any of claims 21-30, wherein the LLZO comprises at least one of (i) Li7-3aLa3Zr2LaO12with L = Al, Ga, or Fe and 0 < a < 0.33; (ii) Li7La3-bZr2MbO12with M = Bi, Ca, or Y and 0 < b < 1; (iii) Li7-cLa3(Zr2-cNc)O12 with N = In, Si, Ge, Sn, V, W, Te, Nb, or Ta and 0 < c < 1; (iv) Li7-xLa3(Zr2-x, Mx)O12 with M = In, Si, Ge, Sn, Sb, Sc, Ti, Hf, V, W, Te, Nb, Ta, Al, Ga, Fe, Bi, Y, Mg, Ca, or combinations thereof and 0 < x < 1; or a combination thereof.

32. The green tape of any of claims 21-31, wherein the green tape exhibits an endothermic signature at a temperature in a range from 190 °C to 210 °C as measured using differential scanning calorimetry.

33. The green tape of any of claims 21-32, comprising a tensile strength of at least 0.5 MPa.

34. The green tape of claim 33, comprising an elongation at break of at least 10%.

35. The green tape of any of claims 21-34, comprising a storage modulus of at least 1 GPa as measured at room temperature.

36. The green tape of any of claims 21-35, wherein the green tape is disposed on a carrier film.

37. The green tape of claim 36, wherein the carrier film comprises silicone-coated polyethylene terephthalate.

38. The green tape of claim 36 or claim 37, wherein a peel force to separate the green tape from the carrier film is less than 0.1 N on average.

39. The green tape of any of claims 21-38, comprising a thickness of 40 μm to 60 μm.

40. The green tape of any of claims 21-39, comprising a length of at least 150 feet.

41. A method of preparing a green tape, comprising: tape casting a slip composition according to any of claims 1-20 onto a carrier film; and evaporating the solvent to produce the green tape.

42. The method of claim 41, further comprising preparing the slip composition, wherein preparing the slip composition comprises: ball milling the solvent and a dispersant to form a first mixture; adding particles of lithium carbonate powder to the first mixture to form a second mixture; balling milling the second mixture; adding the particles of LLZO to the second mixture to form a third mixture; ball milling the third mixture; adding the binder and the plasticizer to form a fourth mixture; and balling milling the fourth mixture.

43. The method of claim 42, wherein the second mixture is ball milled for a time in a range of 36 hours to 72 hours at 20 rpm to 100 rpm before adding the particles of LLZO.

44. The method of claim 42 or claim 43, wherein the third mixture is ball milled for a time in a range from 36 hours to 72 hours at 20 rpm to 100 rpm before adding the binder and the plasticizer.

45. The method of any of claims 41-44, wherein during evaporating a drying front of the green tape is symmetric across a width of the green tape.

46. The method of any of claims 41-45, wherein the carrier film comprises silicone- coated polyethylene terephthalate.

47. The method of any of claims 41-46, wherein the solvent is evaporated at a temperature in a range from 45 °C to 90 °C.

48. The method of any of claims 41-47, wherein the green tape comprises a thickness of 40 μm to 60 μm.

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